nictitating membrane

[nik-ti-tey-ting mem-breyn]

noun

1. a thin membrane, or inner or third eyelid, present in many animals, capable of being drawn across the eyeball, as for protection.

nictitating membrane

/ ˈnɪktɪˌteɪtɪŋ /

noun

1. Also called: third eyelid.  haw. (in reptiles, birds, and some mammals) a thin fold of skin beneath the eyelid that can be drawn across the eye

nictitating membrane

1. A transparent inner eyelid in birds, reptiles, amphibians, and some mammals that protects and moistens the eye without blocking vision.

Word History and Origins

Origin of nictitating membrane¹

1705–15; nictitate ( def. ) + -ing ²